Please note that this recipe only works if you have a skillet that can also go in the oven. You don't want to try transferring the mixture from a skillet to a baking dish before sticking it in the oven, as doing so will completely spoil the light and fluffy texture. Find an oven-safe skillet where the handles won't melt off on you, and then have at it.
4 eggs, separated
1/2 cup milk, cream, or yoghurt (as I like to do)
1 tablespoon whole-wheat flour
2 tablespoons sugar
2 tablespoons butter
4 baby portobello mushrooms, sliced
1 roma tomato, chopped
1/8 cup parmesan cheese
Heat the oven to 350 degrees Fahrenheit.
Beat the egg whites until stiff but not dry.
In a separate bowl, bet the egg yolks together with the yoghurt, flour, salt, and sugar.
Melt the butter in a large ovenproof skillet over medium heat. Once the butter is melted and the skillet is quite warm, fold the egg whites into the egg yolk mixture. Pour the mixture into the skillet and cook on the stove for 2 minutes, sprinkling the mushrooms, tomatoes, and parmesan cheese on top--gently, so as not to ruin the texture of the omelet (if you mix it in any earlier, the lightness of the egg whites will be crushed).
Transfer the skillet into the oven and bake until puffy and browned on top, somewhere between 10 and 15 minutes.
VERDICT? Scrumptious. And much, much fluffier than I ever expected. I don't think I've eaten something quite of this texture before--the closest I can come are some of the homemade pavlovas I've eaten, and even then ... their sugary sweetness is nothing like the light eggy goodness of this omelet. I definitely recommend giving baked omelets a try, if you have the time. They don't even take that long to make!